Ethos Ltd, the country's largest luxury and premium watch retailer, made a weak stock market debut on stock exchanges on Monday. The stock opened for trading at Rs 830 on the BSE, marking a decline of 5.46 per cent. On the National Stock Exchange, the stock opened for trading at Rs 825 marking a decline of 6 per cent. The stock fell as much as 12 per cent or Rs 104 from IPO price.